Fig. 13:48. Helodidae. a, Elodes hausmanni, semidiagramatic 

 longitudinal section through abdomen of larva replenishing its 

 air supply at the water surface; b, Prionocyphon limbafus, dorsal 

 view of pupa (a, Beier, 1949; b, Good, 1924). 



under stones and logs projecting into the water in 

 which the larvae are found. 



The only Nearctic adults which are even partly 

 aquatic are those of Elodes. Following the original 

 description of E. aquatica, Blaisdell wrote, "A colony 

 was discovered on the undersurface of a rather large 

 flat rock, that projected out of and over the surface 

 of the water, at an angle of a few degrees, in a rather 

 swiftly flowing stream. When the rock was lifted up 

 the beetles were disturbed, most of them falling upon 

 the water. As soon as they struck the water, they 

 began to swim briskly and to gyrate as do the Gyri- 

 nids; they dove beneath the surface and swam rapidly 

 under the surface, all endeavoring to return to the 

 rock." 



Wintersteiner recorded larvae of Cyphon sp. from 

 among dead leaves in a pond, and I once found them 

 numerous in wet moss around the edge of a cold spring 

 in wooded hills. R. L. Usinger (in litt.) found them 

 under stones in a spring. 



Pratt took larvae of Prionocyphon discoideus "in 

 the very dirty water in holes in the middle of poplar 

 stumps . . .," and remarked that the body of a dead 

 one had been eaten out and rendered transparent by 

 the larvae of a heleid fly. 



W. E. Snow (unpublished data) has found larvae of 

 species of Cyphon, Elodes, and Prionocyphon in 

 tree holes in Illinois. A. M. Laessle (in litt.) found 

 those of Cyphon spp. (det. van Emden) in the rain- 

 water pockets of Jamaican bromeliads. Picado (1913) 

 reared his Scirtes championi from larvae found in 

 bromeliads in Costa Rica. 



The genera Elodes, Microcara, and Prionocyphon 

 are Holarctic, with additional species in the Neo- 

 tropics: Cyphon is nearly world-wide, Ora is domi- 

 nately New World but recorded also from India, and 

 Scirtes has a host of species in Australia and Africa 

 as well as in the Neotropics. 



Key to the Nearctic Genera of Helodidae 

 Adults 



1. Hind femora much like those of front and middle legs, 



353 



Leech and Chandler: Coleoptera 



not greatly enlarged for jumping; .-purs of hind tibtM 

 small 2 



— Hind femora greatly enlarged, broadened, saltaton.il: 

 spurs of hind tibiae lom», one Ik-nil' at lca.-.t 1 '_' u- lom.' 

 as first tarsal segment (fig. 13:47*) 



2. Meso- and metasternal processes in contact bei 

 middle coxae, separating them t 



— Mososternal process short, narrow, not contacting 

 motasternum, middle coxae contiguous in about apical yj 



3 



3. First segment of hind tarsi flattened above, finel) 

 margined laterally, 2nd with part of hind margin pro- 

 longed, hiding basal section of 3rd; labial palpi with 

 3rd segment arising from side (about mid-point) of 

 2nd (fig. 13:47/"!) Elodes Lntreillo 1796 



— First segment of hind tarsi rounded above, not laterally 

 margined, 2nd not produced posteriorly, not hiding 

 part of 3rd; labial palpi with 3rd segment arising 

 from apex of 2nd Sarabandus Leech 1955 



4. First antennal segment large, fully twice as broad 

 as any of those following, expanded anteriorly; 2nd 

 segment arising from posterior apical angle of 1st 

 and from under a slight margin; 3rd segment very 

 small, 1/2 as long as 2nd; broadly ovate species (fig. 

 13:47/) Prionocyphon Redtenbacher 1858 



— Antennae not as above; body shape various 5 



5. Labial palpi with 3rd segment arising from side (about 

 mid-point) of 2nd (fig. 13 -Alh) 



Microcara Thomson 1859 



— Labial palpi with 3rd segment arising from end of 

 2nd Cyphon Paykull 1 799 



6. Hind coxae meeting along full length of median line, 

 hind margins conjointly forming a subquadrate plate 

 which is not on same plane as intercoxal process of 

 abdomen 14 (fig. 13:47e) Scirtes Illiger 1807 



— Hind coxae touching each other only anteriorly, arcu- 

 ately diverging posteriorly where they are about on a 

 plane with the abdominal process which separates 

 them" Ora Clark 1864 



Key to the Mature Larvae of Certain Genera 

 of Nearctic Helodidae 15 



1. Anterior margin of hypopharynx with a central cone 

 bearing 2 pairs of flat, and usually serrate, spines; 

 head with 1 or 2 ocelli on each side 2 



— Cone of hypopharynx with 1 pair of spines; head with 

 3 ocelli on each side , Elodes Latreille 1796 



2. Abdominal segments 3 to 6 with a regular series of 

 short, flattened differentiated setae along lateral 

 margins 3 



— Sides of abdominal segments with only scattered thin 

 setae, like those of dorsum Cyphon Paykull 1799 



3. Anterior angles of labrum bent under, inner margin 

 projecting from under transverse front margin (fig. 

 13:47a) Prionocyphon Redtenbacher 1858 



— Anterior angles of labrum on same plane as rest, 

 labrum thus simply emarginate (fig. 13:46c, e) 



Scirtes Illiger 1807 



Key to the California Species of Elodes 16 



Adults 



1. Last visible abdominal sternite of male with a deep, 

 rather narrow V-shaped median apical emargination; 



14 This separation will not hold for all exotic species. 



15 With the aid of unpublished data supplied by Drs. W. E. Snow 

 and F. van Emden. However, so few larval helodids have been 

 described that the characters chosen above may not all hold. 



16 The North American species of this genus are difficult to 

 separate, and have not been seriously studied since Horn's paper 



